The Clinical Diagnosis/Behavioral Assessment Core (Core C) will be responsible for ensuring that a common set of age appropriate, interview, behavioral, and diagnostic measures are used in all projects that employ human subjects. The aims of Projects 2 and 3 are highly complementary; thus, they employ similar protocols for the laboratory visits done in the late adolescent age period. As a central activity, the core will conduct structured diagnostic interviews by licensed clinicians on select groups of participants, thus following up on diagnoses made earlier in these longitudinal studies and benefiting Projects 2, 3, 4, and 5. These K-SADS interviews will allow results to be assimilated to the literature on anxiety disorders as defined by DSM-IV. The presence or absence of clinical diagnoses will prominently figure into addressing scientific aims on Projects 2, 3, 4, and 5. Core C will pay for diagnostic interviews and manage the resulting data. Projects 2 and 3 will screen their entire samples for behavioral problems in late adolescence, with the MacArthur Health and Behavior Questionnaire (HBQ) as the main screening instrument. The projects will conduct this screening, but Core C will manage the resulting data in a uniform manner and facilitate analyses across projects. The Trier Social Stress Test (TSST) figures prominently in both Project 2 and 3, and relates conceptually to all projects. Core 2 will facilitate uniform administration of the TSST and conduct behavioral coding of videotapes taken during the TSST. The development and implementation of a coding scheme for affect and behavior during the TSST will be an innovative contribution of Core C. Finally, with our consultant Dr. Kraemer on Project 2, the Core will publish methodological papers on two topics: (1) Clarifying the relationship between categorical field diagnoses of child psychopathology and prior and concurrent dimensional symptom scores from the HBQ and other measures using Receiver Operating Characteristic (ROC) curve approaches. Many developmental factors will be incorporated into these analyses. (2) Examining the psychometric quality of instruments used in the assessment protocols. These latter measures capture key risk factors for adolescent anxiety.